The free fan made Wing Commander Saga: The Darkest Dawn is now available for download. It's a little over 3 gigs.

http://wcsaga.com/news-archive-2012/the-darke … for-launch.html

From the website:
At long last, the day has finally arrived! It has been ten years to the day that the Wing Commander Saga project was officially founded. Through this time, Saga has evolved through a host of iterations, with sometimes frustrating twists and turns and several brick walls. However, we believe that Wing Commander Saga would not be what it is today without the lessons we have learned from each one of those experiences, and we are very excited to finally share the results with you.